How does coronary heart disease develop in a person?

Many things: Many things contribute; some modifiable, others not. Things you can't change include family history, gender, genetics (although you can test for the latter). Things you can change or at least affect: smoking (stop!), exercise, diet, cholesterol & other biomarkers, diabetes/prediabetes/insulin resistance, blood pressure, inflammation. These things damage vessel walls & lead to plaque formation/chd.

CAD: The leading risk factors for CAD are diabetes , hypertension, smoking cholesterol elevation family history age and male gender. Type a personality and stress overall can contrubute.